Nait XS-2 damping factor

Dumping factor or damping factor?

If the latter, then "sufficient".

It's also a singularly useless measurement unless you also know the impedance and phase margin of both the speakers and the cables.  Even then for any competent amp it has no real bearing on sound quality.

Hi Kazu,

Hi-fi World magazine of Feb 2009 quotes a damping factor of 15 for the Naim XS. Is this what you mean?

15 is described by the author as being "typical of a naim amplifier" and manifests itself in such a way that "bass will likely be 'obvious'."

Why do you ask?

Chris

Chris,

15?  Under what conditions?

An amp of itself doesn't have a damping factor as such, it's the amp + load that has a damping factor; and to know what it means for sound reproduction you also need to know the Thiele-Small parameters of the speakers, the size of the room and damping of the room at all frequencies.

Thank you for your responses so quickly! I'm sorry, I would like to mean damping factor! 

I have a brand new ProAc DB1s which was purchased from UK. So, I'm looking for good amplifier for that. ProAc said that Naim XS is reference amplifier for DB1s.

Unfortunately, there are no naim distributor here, in Japan.  I cannot find any amplifier which has such a low damping factor in Japan. 

Luxman, accuphase...etc.  All of Japanese amplifier have hight damping factor. ( 200 > ) 

I'm worry about this situations.

Huge,

The amp was reviewed by David Price. The measurements were made by Noel Keywood. The author quoted above is Keywood. It is not stated whether the mesurements were made in the system as reviewed, or elsewhere with different stuff. However, inside the frontspiece they refer to "in-house test facilities" using kit by Rohde & Schwarz, Hewlett Packard, and Bruel & Kjaer.

The review system contained Yamaha NS1000M speakers, wires unspecified. The source was a record player and valve phonostage.

Price described it as, "the most complete and capable 'affordable' Naim amplifier I've come across". Keywood wrote, "The XS measured very well. It will likely have a smooth sound, with obvious bass in the Naim style, and ameliorate today's bright loudspeakers."

C.

In general if the damping factor is 10 or more then that's OK!  Anything over 20 is completely irrelevant (N.B. need to know the actual impedance of the speaker).

The value of the damping factor depends on the speaker, but the DB1s are stated to be '8Ω nominal impedance' so should, in theory, be a reasonably easy load.  However ProAc haven't published proper specifications so it's impossible to really know.  The XS 2 does have quite a capable power amp, so it should be fine.

Hi Chris,

Thanks, they will have used a test rig to determine the output impedance of the amp, and then assumed an impedance at which to calculate the damping factor (but unless they specify that assumed impedance the actual figure is meaningless!).

Thanks HUGE... do you have any advices for me to choose good amp for DB1s in Japan.

Purely on the basis of their price, and the fact that little monitors always like a bit of power, I'd go for a Supernait2. 

Hi Kazu, I have to agree with HH that the SN2 would be a good match.  Although, in general, PMCs don't seem to be a particularly difficult load, so I think the XS 2 is also well worth a listen.

Look here:

https://www.naimaudio.com/find...roduct_range_tid=All

Huge posted:

Hi Chris,

Thanks, they will have used a test rig to determine the output impedance of the amp, and then assumed an impedance at which to calculate the damping factor (but unless they specify that assumed impedance the actual figure is meaningless!).

According to HiFi World they calc DF by measuring voltage driving an 8 Ohm and then a 4 Ohm load, with 40Hz sine wave at around 4V. Damping Factor is then derived by the formula -  2- V8/V4 / (2xV8/V4)-2  where V8 is voltage across 8 Ohms and V4 voltage across 4 Ohms.

Damping Factor can alternatively be derived by the simple formula - pd / emf - pd    .........   where emf = open circuit volts;  pd = voltage across a load   

Example:  If an amplifier's output was 6V with no load and 5V across an 8 Ohm load,  Damping Factor = 5/(6-5) = 5   Output impedance = Load Z/DF = 8/5 = 1.6 Ohms

I guess its a means of determining something for comparative purposes.

Huge posted:

Hi Kazu, I have to agree with HH that the SN2 would be a good match.  Although, in general, PMCs don't seem to be a particularly difficult load, so I think the XS 2 is also well worth a listen.

Look here:

https://www.naimaudio.com/find...roduct_range_tid=All

It's the ProAc Response DB1, which is very different, hence the idea of the Supernait. The XS would be fine with the PMC DB1i. 

D'oh!

OK, although there's nothing suspicious in the ProAc Response DB1 spec sheet, so if it is a difficult load, then they messed up badly in the design!

Thanks for information HUNGRYHALIBUT, distributors that you showed to me deal with only MU-SO products. 

I agree, it all looks benign, and an XS would no doubt drive them. But a Supernait has that extra welly to really kick them into life. Not that I've ever heard them of course, but having had little speakers before, such as Kans and nSats, I know what a bigger amp can do. 

Kazuhito posted:

Thanks for information HUNGRYHALIBUT, distributors that you showed to me deal with only MU-SO products. 

You'll find that it wasn't me who supplied that link. If you are willing just to buy an amplifier on our recommendation, you can buy from the UK and have it shipped. 

Kazuhito posted:

Thanks for information HUNGRYHALIBUT, distributors that you showed to me deal with only MU-SO products. 

That was me.  OK, then it'll have to be personal import - and you'll be more able to find information on how to do that in Japan than I will.

There are a few people on the forum who do live in Japan and use Naim separates or integrated amps, one of them may be able to give you some help finding out how to do it.  If you want to use a non-Naim amp, then, well this is a Naim forum, so you may do better asking in a different place.

I did read somewhere that proac speakers are damped highly from the type of loading and crossover, hence the recommendation of being good with valve amps which mostly have a very low damping factor of 2 to 5.

Kazu, I've edited your thread title and opening post.

I owned the Nait XS-2 and it is simply an excellent amp, drove my Neat Motive 1 like a charm. It had all the control and finesse you want. No clue what the damping factor is there, but I comfortably say that it is one of the best integrateds in the market. Just go listen and not worry too much about numbers, they don't necessarily correlate to sound quality of sound.

Moussa posted:

I owned the Nait XS-2 and it is simply an excellent amp, drove my Neat Motive 1 like a charm. It had all the control and finesse you want. No clue what the damping factor is there, but I comfortably say that it is one of the best integrateds in the market. Just go listen and not worry too much about numbers, they don't necessarily correlate to sound quality of sound.

Many of us would agree but chap can't go and listen as Japanese dealers only seem to stock <Muso>

Chris

Perhaps once a good second hand unit is found and the voltage issue sorted, Kazuhito will find help from members here to get what he's looking for. Discussion could be continued via private channels. Hope I am not violating forum rules.

Massimo Bertola posted:

Perhaps once a good second hand unit is found and the voltage issue sorted, Kazuhito will find help from members here to get what he's looking for. Discussion could be continued via private channels. Hope I am not violating forum rules.

Max, that would most likely be step too far over the line of the forum's AUP.  

The OP just needs to find a dealer - most likely in North America - who is willing to sell and ship a 115V unit to Japan.  A bigger issue here though is the voltage - not so easily sorted where 100V is required.  While 115V 60Hz units can be used in most parts of Japan, it's not ideal on 100V mains.

Thanks Max, Richard and all, great advices and very kind words...it's very helpful.
 Japanese Mains is 100V 60Hz, So I need a Nait XS2 which is 100V or 115V for US model. But currently the 100V model is not made by Naim factory.  

So, I have two ideas to obtain a Nait XS2 for my ProAc DB1s...

(1) I order a good British technician to replace a transformer to 115V or 100V after I get a second hand/Brand new Nait XS2 UK model.
(2) I purchase a Nait XS2 US model - 115V from Naim USA distributer. However, it costs about USD $3500 plus shipping (I already checked that) it's very much expensive for me.

Please, could you let me know someone who can help me about idea(1) ?

Kazu,

re. option (1) - don't even consider this.  It is not a simple case of taking an off the shelf 100V transformer and fitting it. The transformers are all built for purpose and the amp designed around them.  Even if you personally could find a 100V transformer that worked (sort of), the amp would then need too be tested for safety - to do that you need to pay a lot of money and have at least a couple of units that you are willing to have destroyed.  Unless everything has been very carefully designed it will most likely fail on safety testing alone.  As to what it will sound like if made to work...  who knows?  

Quite apart from that, discussion of any unauthorised modifications to Naim equipment is forbidden here under forum rules.  So, any discussion on this ends here

As far as I'm aware Naim need to be able to sell a certain number of units to make offering a 100V transformer financially viable.  There's a good deal of R&D and testing work involved, as well as committing to the supplier building and stocking a number of transformers, and that costs rather more money than most would imagine.